The pharmacokinetics of escitalopram in patients with hepatic impairment

Population pharmacokinetics model for escitalopram in Chinese psychiatric patients: effect of CYP2C19 and age

Objective: To establish a population pharmacokinetic model in Chinese psychiatric patients to characterize escitalopram pharmacokinetic profile to identify factors influencing drug exposure, and through simulation to compare the results with the established therapeutic reference range.

Methods: Demographic information, dosing regimen, CYP2C19 genotype, concomitant medications, and liver and kidney function indicators were retrospectively collected for inpatients taking escitalopram with therapeutic drug monitoring from 2018 to 2021. Nonlinear mixed-effects modeling was used to model the pharmacokinetic characteristics of escitalopram. Goodness-of-fit plots, bootstrapping, and normalized prediction distribution errors were used to evaluate the model. Simulation for different dosing regimens was based on the final estimations.

Results: The study comprised 106 patients and 337 measurements of serum sample. A structural model with one compartment with first-order absorption and elimination described the data adequately. The population-estimated apparent volume of distribution and apparent clearance were 815 and 16.3 L/h, respectively. Age and CYP2C19 phenotype had a significant effect on the apparent clearance (CL/F). CL/F of escitalopram decreased with increased age, and CL/F of poor metabolizer patients was significantly lower than in extensive and immediate metabolizer patients. The final model-based simulation showed that the daily dose of adolescents with poor metabolizer might be as high as 15 mg or 20 mg and referring to the therapeutic range for adults may result in overdose and a high risk of adverse effects in older patients.

Conclusion: A population pharmacokinetics model of escitalopram was successfully created for the Chinese population. Depending on the age of the patients, CYP2C19 genotype and serum drug concentrations throughout treatment are required for adequate individualization of dosing regimens. When developing a regimen for older patients, especially those who are poor metabolizers, vigilance is required.

Population pharmacokinetic/pharmacodynamic modeling of delayed effect of escitalopram-induced QT prolongation

BACKGROUND

A thorough QT study identified that escitalopram-induced QT prolongation was delayed. This study thus aimed to develop a population pharmacokinetic (PK)/pharmacodynamic (PD) model to characterize the relationship between escitalopram concentrations and the delayed effect on QT prolongation.

METHODS

The data of completed subjects who had placebo (n=36) and a single dose of 20 mg escitalopram (n=33) from a previous thorough QT study were used. Population PK/PD analysis was performed by nonlinear mixed-effects modeling. A escitalopram concentration-drug effect model was developed with estimated individual PK and baseline QT parameters. To explain the relationship between escitalopram concentrations and QT prolongation delay, an effect compartment model was utilized.

RESULTS

A two-compartment model with first-order absorption and lag time and first-order elimination adequately described the PK of escitalopram. The circadian rhythm of baseline QT interval was best explained by two harmonic cosine functions. A linear model properly characterized escitalopram-induced QT prolongation. The average estimated maximal QT prolongation was 5.4 ms (range: 1.9-7.6 ms). The equilibrium half-life of delayed QT prolongation was 1.9 h. The drug effect of QTc change compared with that at baseline remained relatively constant from 1.3 to 3.5 ms over 24 h, and the maximum QTc change occurred with a 3-h delay after the time to the maximum plasma concentration.

LIMITATIONS

We did not include genetic polymorphisms, such as CYP2C19, as potential covariates owing to limited information.

CONCLUSIONS

These results may provide useful information on when to monitor electrocardiogram in patients who require intensive care after drug administration.

<p>Comparison of Bioavailability and Bioequivalence of Generic and Brand Name Formulations of Escitalopram Oxalate Tablets in Healthy Chinese Population Under Fasting and Fed Conditions</p>

Purpose

This study compared the bioequivalence of two formulations of escitalopram oxalate 20 mg tablets in terms of bioavailability and tolerability in healthy Chinese male and female subjects.

Patients and Methods

A randomized, single-blind, two-period, two-sequence crossover study was performed under fasting and fed conditions, with a 21-day washout period. In total, 24 healthy subjects (18 males and 6 females) were enrolled in the fasting test and the fed test, respectively. Blood samples were collected over 168 h post-dose in each period. The concentrations of escitalopram in plasma were determined by high-performance liquid chromatography coupled with a tandem mass spectrometry. Pharmacokinetic parameters used for bioequivalence assessment were determined from the drug concentration data using noncompartmental analysis.

Results

All subjects showed good medication compliance. The 90% confidence intervals (CIs) for the geometric mean ratios of AUC_0-t, AUC_0-∞, and C_max were within the bioequivalence acceptance criteria (80.00% to 125.00%). Adverse events were recorded and no deaths or serious adverse events (SAEs) occurred.

Conclusion

Escitalopram oxalate 20 mg tablets produced in China were bioequivalent to the reference formulation (Lexapro^®) in healthy Chinese male and female subjects under fasting and fed conditions.

Predicting Escitalopram Exposure to Breastfeeding Infants: Integrating Analytical and In Silico Techniques

BACKGROUND

Escitalopram is used for post-partum depression; however, there are limited pharmacokinetic data of escitalopram in milk and plasma of infants breastfed by women taking the drug.

OBJECTIVE

The objective of this study was to apply physiologically-based pharmacokinetic (PBPK) modelling to predict infant drug exposure (plasma area under the curve from time zero to infinity [AUC_∞]) based on drug monitoring data of escitalopram in breast milk.

METHODS

Using a newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, we quantified escitalopram concentrations in milk samples of 18 breastfeeding women with escitalopram therapy at steady state, collected at three to five time points. The escitalopram concentrations in breast milk were used with infant feeding parameters from the literature to simulate infant daily dose. We used PK-Sim^® to develop an adult PBPK model for escitalopram and extrapolated it to a population of 1600 infants up to 12 months of age. An integration of the simulated infant daily dose and the virtual infants with variable physiological-pharmacological parameters was used to predict drug exposure (plasma AUC_∞) distribution in the population of infants breastfed by women receiving escitalopram 20 mg/day.

RESULTS

Escitalopram concentrations in milk were 50 ± 17 ng/mL (mean ± standard deviation). The simulated infant plasma AUC_∞ following escitalopram exposure through breast milk was low, with a median of 1.7% (range 0.5-5.9%) of the corresponding maternal plasma AUC_∞, indicating no substantial exposure.

CONCLUSIONS

Infant exposure levels to escitalopram in breast milk are low. A PBPK modeling approach can be used to translate data on drug monitoring in milk into a population distribution of infant plasma levels for drug safety assessment.

A Prediction Model of Drug Exposure in Cirrhotic Patients According to Child-Pugh Classification

BACKGROUND AND OBJECTIVE

Prediction of drug clearance in liver cirrhosis patients is currently based on in vitro-in vivo extrapolation and physiologically-based pharmacokinetic models. No static model for this purpose has been described. The objectives of this study were to (1) derive a static model for predicting drug exposure in cirrhotic patients, and (2) to evaluate the model on a large set of published data.

METHODS

The impact of cirrhosis was characterized by the ratio of the total and unbound drug area under the concentration-time curve (AUC) in cirrhotic patients to the AUC measured in healthy subjects These ratios were predicted for Child-Pugh classes A, B, and C. The AUC ratios observed in published data were compared with AUC ratios predicted by the model.

RESULTS

Among 171 drugs examined, 83 published AUC ratios for 45 drugs in cirrhotic patients were available for analysis. The mean ± standard deviation relative prediction error for the total and unbound AUC ratios was 0.22 ± 0.58 and 0.24 ± 0.56, respectively. There were four outliers among the 83 predicted values. Simulations showed that the prediction error was negligible provided that the hepatic extraction coefficient was less than 0.8.

CONCLUSIONS

For mild and moderate cirrhosis (classes A and B), the predicted unbound AUC ratio is typically approximately 2 and 3.5, respectively, for most drugs. In the absence of data in cirrhotic patients, the drug dose might be empirically reduced by these factors. In severe cirrhosis (class C), our model may help clinicians to adjust their prescriptions.

Pharmacokinetics of antidepressants in patients with hepatic impairment

Appropriate use of antidepressant in patients with hepatic impairment requires careful consideration of how the hepatic illness may affect pharmacokinetics. This review aims to analyze pharmacokinetic profile, plasma level variations so as the metabolism of several antidepressants relating to their use in patients with an hepatic impairment. Due to the lack of data regarding hepatic impairment itself, the review is focused mainly on studies investigating pharmacokinetics in hepatic cirrhosis or alcohol-related conditions. More data on reduced hepatic metabolism can be extrapolated by drug studies conducted in elderly populations. Dose adjustment of antidepressants in these patients is important as most of these drugs are predominantly metabolized by the liver and many of them are associated with dose-dependent adverse reactions. As no surrogate parameter is available to predict hepatic metabolism of drugs, dose adjustment according to pharmacokinetic properties of the drugs is proposed. There is a need for a more balanced assessment of the benefits and risks associated with antidepressants use in patients with hepatic impairment, particularly considering pharmacokinetic profile of the drugs to ensure that patients, who would truly benefit from these agents, are not denied appropriate treatment. In conclusion, kinetic studies for centrally acting drugs including antidepressants with predominant hepatic metabolism should be carried out in patients with liver disease to allow precise dose recommendations for enhanced patient safety.

Review article: depression and the use of antidepressants in patients with chronic liver disease or liver transplantation

BACKGROUND

The scale of depression in patients with chronic liver disease (CLD) and those who have received orthotopic liver transplantation (OLT) is poorly characterised. Clinicians are uncertain of how best to manage depression within these patients.

AIMS

To review the literature evaluating both the prevalence and impact of depression in patients with CLD and post-OLT, and to assess the safety and efficacy of antidepressant use within this context.

METHODS

A PubMed search using the phrases 'chronic liver disease', 'cirrhosis', 'liver transplantation', 'depression', 'antidepressant' and the names of specific causes of liver disease and individual antidepressants.

RESULTS

Over 30% of cirrhotic patients have depressive features, and they experience worse clinical outcomes than nondepressed cirrhotic patients. CLD patients with chronic hepatitis C are particularly prone to depression, partly related to the use of interferon therapy. OLT patients with depression have higher mortality rates than nondepressed patients; appropriate antidepressant use reverses this effect. Selective serotonin reuptake inhibitors (SSRIs) and selective noradrenaline reuptake inhibitors (SNRIs) are effective and generally safe in both CLD and OLT patients.

CONCLUSIONS

Depression is much more prevalent in CLD or OLT patients than is generally recognised, and it adversely affects clinical outcomes. The reasons for this relationship are complex and multifactorial. Antidepressants are effective in both CLD and post-OLT, although lower doses or a reduced dosing frequency may be required to minimise side effects, e.g. exacerbation of hepatic encephalopathy. Further research is needed to establish optimal management of depression in these patients, including the potential role of nonpharmacological treatments.

Relevance of Liver Failure for Anti-Infective Agents: From Pharmacokinetic Alterations to Dosage Adjustments

The liver is a complex organ with great ability to influence drug pharmacokinetics. Due to its wide array of function, its impairment has the potential to affect bioavailability, enterohepatic circulation, drug distribution, metabolism, clearance, and biliary elimination. These alterations differ widely depending on the cause of the liver failure, if it is acute or chronic in nature, the extent of impairment, and comorbid conditions. In addition, effects on liver functions do not occur in a proportional or predictable manner for escalating degrees of liver impairment. The ability of hepatic alterations to influence PK is also dependent on drug characteristics, such as administration route, chemical properties, protein binding, and extraction ratio, among others. This complexity makes it difficult to predict what these effects have on drugs. Unlike certain classes of agents, efficacy of anti-infectives is most often dependent on fulfilling pharmacokinetic/pharmacodynamic targets, such as C_max/MIC, AUC/MIC, T_>MIC, IC₅₀/EC₅₀, or T>EC₉₅. Loss of efficacy, or conversely, increased risk of toxicity may occur in certain circumstances of liver injury. Although important to consider these potential alterations and their effects on specific anti-infectives, many lack data to constitute specific dosing adjustments, making it important to monitor patients for effectiveness and toxicities of therapy.

Brivaracetam disposition in mild to severe hepatic impairment

Brivaracetam is a high-affinity synaptic vesicle protein 2A (SV2A) ligand in clinical development for epilepsy. This open-label, single-dose study evaluated brivaracetam disposition in participants with different degrees of hepatic impairment versus matched healthy controls. Twenty-six participants (38-72 years; 19 males and 7 females) with hepatic impairment classified by Child-Pugh score (mild, n = 6; moderate, n = 7; severe, n = 7) or normal hepatic function (n = 6) received a single oral dose of 100 mg brivaracetam. The pharmacokinetics of brivaracetam and its three main metabolites (acid, hydroxy, hydroxyacid) were determined and correlated with impairment severity. Dynamic liver function tests correlated with hepatic impairment severity. The plasma half-life of brivaracetam was 9.8, 14.2, 16.4, and 17.4 hours and the area under the plasma concentration-time curve was 29.7, 44.6, 46.7, and 47.1 µg h/mL in healthy controls and participants with mild, moderate, and severe liver impairment, respectively. Production of the acid metabolite was increased and the hydroxylated metabolites were decreased in participants with hepatic impairment versus healthy controls. Exposure to brivaracetam increased by 50-60% in patients with hepatic impairment, irrespective of severity. The relative importance of biotransformation pathways was altered; cytochrome P450 (CYP)-dependent hydroxylation decreased; CYP-independent acid metabolite formation increased concomitantly.

Escitalopram: a review of its use in the management of major depressive disorder in adults

Escitalopram (escitalopram oxalate; Cipralex, Lexapro), a selective serotonin reuptake inhibitor (SSRI) indicated for the treatment of major depressive disorder (MDD), demonstrates a highly selective and potent, dose-dependent inhibition of the human serotonin transporter, inhibiting serotonin reuptake into presynaptic nerve terminals and thus increasing serotonergic activity in the CNS. With regard to primary endpoints (such as improved scores on the Montgomery-Asberg Depression Rating Scale [MADRS] and the Hamilton Depression Rating Scale [HAM-D]), escitalopram was generally more effective than placebo, at least as effective as citalopram, and generally at least as effective as other comparator drugs, including the SSRIs fluoxetine, paroxetine and sertraline, the serotonin-noradrenaline (norepinephrine) reuptake inhibitors (SNRIs) venlafaxine extended release and duloxetine, and the aminoketone bupropion in adult patients with MDD in short-term, well designed trials. Moreover, it demonstrated a rapid onset of antidepressant action. Escitalopram was also found to be cost effective in several studies, dominating other SSRIs and venlafaxine extended release. Maintenance therapy is commonly required to prevent recurrence of depression. Long-term trials corroborated short-term results, with escitalopram demonstrating greater efficacy than placebo in relapse prevention. Additionally, escitalopram was at least as effective as citalopram, paroxetine and duloxetine in long-term comparative trials. Escitalopram has a predictable tolerability profile with generally mild to moderate and transient adverse events, and a low propensity for drug interactions. Sexual dysfunction with escitalopram treatment appeared to occur to a similar or lower extent to that with paroxetine (another SSRI), to a similar or greater extent to that with the SNRI duloxetine, and to a greater extent than that with the aminoketone bupropion. Thus, escitalopram is an effective and generally well tolerated treatment for moderate to severe MDD. Escitalopram, like other SSRIs, is an effective first-line option in the management of patients with MDD.

Effect of age, weight, and CYP2C19 genotype on escitalopram exposure

The purpose of this study was to characterize escitalopram population pharmacokinetics (PK) in patients treated for major depression in a cross-national, US-Italian clinical trial. Data from the 2 sites participating in this trial, conducted at Pittsburgh (United States) and Pisa (Italy), were used. Patients received 5, 10, 15, or 20 mg of escitalopram daily for a minimum of 32 weeks. Nonlinear mixed effects modeling was used to model the PK characteristics of escitalopram. One- and 2-compartment models with various random effect implementations were evaluated during model development. Objective function values and goodness-of-fit plots were used as model selection criteria. CYP2C19 genotype, age, weight, body mass index, sex, race, and clinical site were evaluated as possible covariates. In total, 320 plasma concentrations from 105 Pittsburgh patients and 153 plasma concentrations from 67 Pisa patients were available for the PK model development. A 1-compartmental model with linear elimination and proportional error best described the data. Apparent clearance (CL/F) and volume of distribution (V/F) for escitalopram without including any covariates in the patient population were 23.5 L/h and 884 L, respectively. CYP2C19 genotype, weight, and age had a significant effect on CL/F, and patient body mass index affected estimated V/F. Patients from Pisa, Italy, had significantly lower clearances than patients from Pittsburgh that disappeared after controlling for patient CYP2C19 genotype, age, and weight. Postprocessed individual empirical Bayes estimates on clearance for the 172 patients show that patients without allele CYP2C19(*)2 or (*)3 (n = 82) cleared escitalopram 33.7% faster than patients with heterogeneous or homogeneous (*)2 or (*)3 ((*)17/(*)2, (*)17/(*)3, (*)1/(*)2, (*)1/(*)3, (*)2/(*)2, (*)2/(*)3, and (*)3/(*)3, n = 46). CL/F significantly decreased with increasing patient age. Patients younger than 30 years (n = 45) cleared escitalopram 20.7% and 42.7% faster than patients aged 30 to 50 years (n = 84) and older than 50 years of age (n = 43), respectively. CYP2C19 genotype, age, and weight strongly influenced the CL/F of escitalopram. These variables may affect patient tolerance of this antidepressant and may provide important information in the effort to tailor treatments to patients' individual needs.

Factors that impact choice of antidepressant treatment in medically complex patients

In medically complex patients with multiple comorbid illnesses who require concomitant medications, selecting the optimal antidepressant (ie, low risk of adverse effects and/or pharmacokinetic interactions) for an individual patient is critical for positive long-term patient outcomes. The serotonin-norepinephrine reuptake inhibitors (SNRls) are increasingly being used as first-line treatment for major depressive disorder (MDD) and may prove beneficial for treatment of medically complex patients.Thus, it is key for clinicians to evaluate the differences in the pharmacokinetic and tolerability profiles of the SNRI class of antidepressants, evaluating differences both within the class and compared with other antidepressants used to treat MDD.

Escitalopram for the treatment of major depression and anxiety disorders

Escitalopram is the S-enantiomer of the selective serotonin reuptake inhibitor (SSRI) citalopram, which contains equal amounts of the S- and R-forms in a racemic mixture. Escitalopram is the most selective SSRI, with almost no significant affinity to other tested receptors. It has been demonstrated that it is escitalopram that carries the therapeutic potential of citalopram, and has statistically superior and clinically relevant properties compared with citalopram. Escitalopram is at least as effective in the treatment of depression and anxiety as other SSRIs, as well as venlafaxine, bupropion and duloxetine. Owing to multiple metabolic degrading pathways, the clinically relevant interactions of escitalopram with other drugs are minimal. Compared with other antidepressants, escitalopram is generally better tolerated, its onset of action is relatively fast, and its use may have cost-effectiveness and cost-utility advantages. Escitalopram is an effective first-line option in the management of patients with major depression, including severe forms, and various anxiety disorders.

Escitalopram therapy for major depression and anxiety disorders

BACKGROUND

Randomized controlled clinical trials have demonstrated that escitalopram is efficacious in a range of mood and anxiety disorders, but the individual trials are insufficiently large to allow a full exploration of its tolerability.

OBJECTIVE

To assess the tolerability and safety of escitalopram through analysis of all randomized controlled clinical trials in major depressive disorder and anxiety disorders.

METHODS

Analyses of tolerability were based on data from all available randomized, double-blind, controlled studies completed by December 2006 in which escitalopram was compared with placebo or active compounds (citalopram, fluoxetine, paroxetine, sertraline, venlafaxine). Adverse events (AEs) that occurred more frequently with escitalopram than with placebo were listed, and tolerability and safety were evaluated.

RESULTS

Nausea was the only AE with an incidence greater than or equal to 10% and 5 percentage points greater than with placebo during short-term treatment. In general, AEs were mild to moderate in severity. AEs related to sexual dysfunction were similarly frequent with escitalopram and citalopram, but were higher with paroxetine. No suicide occurred among escitalopram-treated patients, and there were no significant differences between escitalopram and placebo in incidence of suicidal behavior, measured by self-harm and suicidal thoughts. The 8 week withdrawal rate due to AEs was higher with escitalopram than with placebo (7.3% vs 2.8%; p < 0.001) but lower than with paroxetine (6.6% vs 9.0%; p < 0.01) or venlafaxine (6.1% vs 13.2%; p < 0.01) (Fisher's Exact test, 2 tailed). Compared with paroxetine, escitalopram resulted in significantly fewer discontinuation symptoms (average increase in Discontinuation Emergent Signs and Symptoms Scale of 1.6 vs 3.9; p < 0.01). There were no clinically relevant changes in clinical laboratory values in patients treated with escitalopram. Mean weight change after 6 months of treatment with escitalopram (0.58 +/- 2.63 kg) was similar to that with placebo (0.15 +/- 2.33 kg). The incidence of cardiovascular events was similar to that with placebo. The risk of AEs was no higher in special patient populations, such as the elderly (> or =65 y of age) or those with hepatic dysfunction.

CONCLUSIONS

Based on data from randomized controlled trials involving more than 4000 escitalopram-treated patients, escitalopram (10-20 mg/day) is safe and well tolerated in short- and long-term treatment.

The clinical pharmacokinetics of escitalopram

Escitalopram is the (S)-enantiomer of the racemic selective serotonin reuptake inhibitor antidepressant citalopram. Clinical studies have shown that escitalopram is effective and well tolerated in the treatment of depression and anxiety disorders. Following oral administration, escitalopram is rapidly absorbed and reaches maximum plasma concentrations in approximately 3-4 hours after either single- or multiple-dose administration. The absorption of escitalopram is not affected by food. The elimination half-life of escitalopram is about 27-33 hours and is consistent with once-daily administration. Steady-state concentrations are achieved within 7-10 days of administration. Escitalopram has low protein binding (56%) and is not likely to cause interactions with highly protein-bound drugs. It is widely distributed throughout tissues, with an apparent volume of distribution during the terminal phase after oral administration (V(z)/F) of about 1100L. Unmetabolised escitalopram is the major compound in plasma. S-demethylcitalopram (S-DCT), the principal metabolite, is present at approximately one-third the level of escitalopram; however, S-DCT is a weak inhibitor of serotonin reuptake and does not contribute appreciably to the therapeutic activity of escitalopram. The didemethyl metabolite of escitalopram (S-DDCT) is typically present at or below quantifiable concentrations. Escitalopram and S-DCT exhibit linear and dose-proportional pharmacokinetics following single or multiple doses in the 10-30 mg/day dose range. Adolescents, elderly individuals and patients with hepatic impairment do not have clinically relevant differences in pharmacokinetics compared with healthy young adults, implying that adjustment of the dosage is not necessary in these patient groups. Escitalopram is metabolised by the cytochrome P450 (CYP) isoenzymes CYP2C19, CYP2D6 and CYP3A4. However, ritonavir, a potent inhibitor of CYP3A4, does not affect the pharmacokinetics of escitalopram. Coadministration of escitalopram 20mg following steady-state administration of cimetidine or omeprazole led to a 72% and 51% increase, respectively, in escitalopram exposure compared with administration alone. These changes were not considered clinically relevant. In vitro studies have shown that escitalopram has negligible inhibitory effects on CYP isoenzymes and P-glycoprotein, suggesting that escitalopram is unlikely to cause clinically significant drug-drug interactions. The favourable pharmacokinetic profile of escitalopram suggests clinical utility in a broad range of patients.

Escitalopram: a review of its use in the management of anxiety disorders

Escitalopram (Cipralex, Lexapro, Seroplex, Sipralexa), the therapeutically active S-enantiomer of racemic citalopram (RS-citalopram), is a potent and highly selective serotonin reuptake inhibitor. It is effective and generally well tolerated in the treatment of moderate to severe generalised anxiety disorder (GAD) or social anxiety disorder (SAD), panic disorder (with or without agoraphobia) as well as obsessive-compulsive disorder (OCD). Moreover, escitalopram is at least as effective as paroxetine for the treatment of GAD, SAD or OCD and appears to achieve a more rapid response than racemic citalopram in the management of panic disorder. Generally, it has a more favourable tolerability profile than paroxetine in terms of fewer discontinuation symptoms. In addition, a favourable pharmacokinetic profile permits once-daily administration of the drug. Additional comparative studies are required to definitively position escitalopram with respect to other SSRIs and venlafaxine. Nevertheless, available clinical data indicate that escitalopram is an effective first-line treatment option for the management of GAD, SAD, panic disorder and OCD.